Pain is probably the most fundamental and primitive sensation. It is distributed more or less all over the body. It is protective in nature and always indicates some serious trouble in the locality, such as a structural damage or a serious functional or metabolic derangement.It is difficult to define pain, as the feeling is purely subjective. It may be succinctly described as 'what the patient says it hurts'. Dorland's Medical Dictionary defined pain as 'more or less localised sensation of discomfort, distress or agony resulting from the stimulation of specialised nerve endings'. Fields defined pain as 'an unpleasant sensation that is perceived as arising from a specific region of the body and is commonly produced by processes which damage or are capable of damaging bodily tissue'. In other words, pain is a somatopsychic phenomenon.Pain is essentially an abnormal affective state that is aroused by the pathological activity of a specific sensory system. The purpose of this book was an attempt to cover the literature on pain and its management.